Investigation of a MOSFET dosimetry system for midpoint dose verification in prostate 3D CRT/IMRT.
The suitability of MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) for use in in-vivo dosimetry for IMRT prostate treatment and patient setup errors has been investigated in this work. MOSFETs were placed on entrance and exit surfaces of a number of different phantoms (with varying complexities from homogeneous to anthropomorphic). Dose measurements were then used to calculate a midpoint dose, which was compared with an IC placed at the isocentre. The agreements found between the calculated (MOSFETs) and the measured midpoint dose (IC) was: 0.7% for a prostate treatment verification and 3.5% for an IMRT treatment. MOSFETs placed on entry and exit surfaces can detect patient setup offsets of 2 cm, but do not have the sensitivity to confidently detect offsets of 1 cm or smaller.
Wiese
T
T
School of Chemistry and Physics, Department of Physics, University of Adelaide, Adelaide, Australia. timothy.wiese@adelaide.edu.au
Bezak
E
E
Nelligan
R
R
D001822:Body Burden; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000295:instrumentation* / Q000379:methods; D012062:Relative Biological Effectiveness; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014173:Transistors, Electronic